ABSTRACT Urologic Chronic Pelvic Pain Syndrome (UCPPS) encompasses two highly prevalent chronic urologic pain disorders, interstitial cystitis/ bladder pain syndrome (IC/BPS) in men and women, and chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) in men. Like many chronic pain disorders, UCPPS is poorly understood and characterized, and treatment is mostly empirical and unsatisfactory. The Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network was established by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), to study the etiology and treated natural history of UCPPS, to inform better treatments and management of symptoms through improved designs of clinical trials, and to identify clinical factors and research measurements to define clinically relevant sub-groups of these patients. The MAPP Research Network is currently completing enrollment of participants into the Trans-MAPP Symptom Patterns Study (SPS), which involves integrated phenotyping of UCPPS participants at baseline and during a 36-month longitudinal, observational period. The SPS includes measures to refine UCPPS subgrouping, identify symptom trends, and discover associated risk factors and biological correlates to progression profiles. Integrated within the central protocol are studies to correlate clinical and biological profiles with response to selected UCPPS therapies (the Analysis of Therapies during Longitudinal Assessment of Symptoms [ATLAS] study). The current funding period ends in June 2019. We propose a three-year funding extension, through June 2022. During the proposed three-year extension, we aim to accomplish the following: SPECIFIC AIM 1: To Obtain an Additional 12 Months of Follow-up in the MAPP- II SPS. The MAPP-II SPS was designed to follow UCPPS participants for up to three years. By extending the timeframe for longitudinal follow-up from July 2019 to July 2020, the number of UCPPS participants followed for three years in the SPS will almost double (from 198 to 384). This additional data will substantially increase the ability of MAPP investigators to examine patterns and predictors of UCPPS symptoms over time. SPECIFIC AIM 2: To Observe Additional ATLAS Events in the MAPP-II SPS. A major focus of the MAPP-II SPS is to correlate individual participant phenotypes with UCPPS treatment response. To accomplish this, SPS participants complete a phenotyping assessment before and after starting new UCPPS treatments (ATLAS study). The additional year of follow-up will provide time for new treatment `events' to occur which can be included in this important analysis. SPECIFIC AIM 3: To Conduct Analyses of MAPP-II Data. The current funding period provides inadequate time for MAPP investigators to analyze the data collected as part of the SPS. Therefore, the final two years of the proposed three-year MAPP-II extension will be devoted exclusively to data analysis and manuscript preparation.